Fibrous jacket for insulated conductors



mnous JACKET Fon msummn coNDuoToRs Filed Jim@ 9,1193@ INVENTOR #wma/vr f? MMsx/x ATTORNE Patented Apr. 8, 1941 FBROUS JACKET FOR INSULATED CNDUCTORS Anthony P. Hinsky, Brooklyn, N. Y., assigner to Pyro Products Corporation, Brooklyn, N. Y., a

corporation of New York Application .lune 9, 1939, Serial No 278,223

Z Clair-ns.

This invention relates to an electric conductor and particularly to a conductor employing one or more brous jackets arranged directly thereon, and the object of the invention is to provide an innermost braided fibrous jacket having incorporated therein and as a part thereof a plurality of circumferentially spaced and longitudinally extending strands t provide a jacket which will vprevent creeping and longitudinal shifting thereof on the conductor, especially in applying Various treating and coating compounds or saturants to the jacketed conductor, and in passing the same through dies employed to remove surplus coating materials therefrom, and with these and other objects in. View the invention consists in a conductor of the class and for the purpose specied which is simple in construction, efficient in use, and which is constructed as hereinafter described and claimed.

The invention is fully disclosed in the following specification, of which the accompanying drawing forms a part, in which the separate parts of my improvement are designated by suitable reference characters in each of the views, and in which:

Fig. 1 is a detailed view of a part of a conductor showing a part of one of the jackets arranged thereon.

Fig. 2 is a cross section of the structure shown in Fig. 1.

Fig. 3 is a view similar to Fig. 1 showing the arrangement of another jacket on the rst mentioned jacket.

Fig. 4 is a cross section of the structure as shown in Fig. 3.

It has long been the practice in the making of insulated wires and conductors to employ woven or braided fabric as a sheathing material, and for this purpose a braid of the basket weave type has often been used. One strong objection to this type of sheathing, however, is the high degree of longitudinal stretch of the braided fabric which permits slipping or creeping of the fabric in the subsequent treating and handling of the conductor as well as in the use thereof This longitudinal slipping is especially noticeable and objectionable when the fabric sheath is arranged directly on the wire or conductor since the braid cannot imbed itself in the' conductor. In the present invention, a new type of braid is provided which obviates the old diiculties and makes possible the formation of an insulating sheath on a conductor which is not subject to longitudinal slipping or creeping, and which at the same time may be produced as readily and as inexpensively as the conventional fabric sheathing.

In Figs. 1 and 2 of the drawing is shown a conductor or wire l having a sheath I I comprising a braid of spirally wrapped strands I 2 and I3. The strands I2 are wound in a clockwise direction and the strands i3 in a counterclockwise direction, and the sheath II is braided with a longitudinal lay of strands or ller cords I4 spaced circumferentially of the conductor and arranged between the respective strands I2 and I3.

The strands i2 and I3 may comprise any desired Vnatural or synthetic l'ibre and may be of a size and arranged in a manner on the conductor to best satisfy 'the requirements in various types of conductors. The ller cords I4 may also comprise any desired fibre or suitable material of a non-conducting nature and it will be apparent that these cords may each comprise relatively large unitary members or may be made up of a plurality of relatively small twisted members. It is important, however, that the ller cords I4 be of a relatively non-extensible nature. By arranging the non-extensible cords I4 between the counter-wound strands I2 and I3, it will be apparent that the normal stretching properties characteristic of a braid will be destroyed. In other words, a sheathing fashioned in the manner shown in Figs. 1 and 2 of the drawing will not stretch or creep in the subsequent treating and handling of the conductor.

In practice it is generally -advisable to employ a plurality of fabric sheaths in forming the complete insulation of a conductor. In Figs. 3 and 4 of the drawing there is shown an arrangement including a conductor I5, an inner sheath I5 and an outer sheath Il, The inner sheath IB is similar to the sheath II shown in Fig. 1, and comprises a braid of counter-wound strands I8 and I9 having longitudinal filler cords 20 arranged therebetween at intervals spaced circumferentially of the conductor. The outer sheath I'l comprises plain or conventional braid having counter-wound strands ZI and 22.

The inner sheath I l has the non-extensible properties described in connection with the sheath I I while the outer sheath IT is freely extensible. The irregularities on the contacting surfaces of the sheaths, however, interiit with each other, and serve to substantially anchor the two sheaths together; and in effect the objectional stretching properties of the outer sheath will, therefore, be overcome. It will be apparent, however, that there is sufficient flexibility and freedom of movement between the inner and outer sheaths to permit the extensible properties of the outer sheath to compensate for the elongation of the outer surface of thel sheath when the conductor is sharply bent. In the outer sheath a compensating stretch of the fabric is necessary to prevent rupturing of the fabric, and it will be apparent that as successive additional sheaths are added the extensibility of the sheath becomes increasingly important due to the increased relative elongation of bent portions of the conductor as the external diameter is increased. In this connection, it should be noted that if a single sheath such as the sheath ll is employed having non-extensible filler cords there may be a slight tendency to rupture the cords if the conductor is very sharply bent. However, in a sheath arranged directly on the conductor the elongation of the outer surface of the sheath will not be appreciable, and even a relatively non-extensible fibre will generally have enough resilience t compensate for this slight elongation. When one or more outer sheaths are employed over the inner non-extensible sheath, it will be apparent that the increased stiiening of the conductor as well as the pressure of the successive sheaths upon the inner sheath tends to diminish the strain which might; be set up in the iiller cords and to prevent rupturing of the cords.

It will be apparent that the non-extensible properties of the improved insulating jacket are of special significance in the operations of treating and coating the jacket. Suitable compounds may be applied to the jacket in excess amounts and the excess may then be removed by drawing the conductor through suitable dies without any danger of objectional creeping or slipping of the jadket.

While in Figs. 3 and 4 of the drawing a single outer sheath has been shown over the inner nonextensible sheath, it will be understood that two or more outer sheaths may be employed depending upon the insulation and wear requirements for different conductors, It will further be apparent that any and all layers or sheaths of fabric may be treated to impart insulating and Wea-ther and wear resisting properties to the jacket and the outer fabric layers or sheaths may be characterized to provide ornamentation and identification means on the conductor. These features represent more or less conventional practices in the art and do not in any way effect the improved sheathing structure disclosed.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is:.

l. In insulated conductors, a non-extensible fibrous insulating body arranged directly upon a conductor member, said body including an inner sheath comprising a braid of fabric strands, a plurality of non-extensible Afibrous strands arranged within the braid of said sheath and extending longitudinally of the conductor at circumferentially spaced intervals, said body further including an outer sheath comprising a braid of fabric strands, the braid of said outer sheath having normally extensible properties, and the strands of said outer sheath being in close and interfitting engagement with the strands of said non-extensible inner sheath, whereby the extensible properties of said outer sheath are checked.

2. In an insulated conductor, an insulating jacket comprising a plurality of braided sheaths, the innermost sheath having relatively non-extensible fibrous means incorporated therewith to prevent longitudinal creeping of said sheath, and the irregular contacting surfaces of adjacent braided sheaths interiitting with each other, whereby said non-extensible sheath will prevent longitudinal creeping of the entire jacket.

, ANTHONY P. HINSKY. 

